[PDFBOX-4411] Support caching of ICC based color spaces

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.13
• Fix Version/s: 2.0.14, 3.0.0 PDFBox
• Component/s: Rendering
• Flags: Patch
• Assignee: Tilman Hausherr
• Reporter: Itai Shaked
• Created: 18/Dec/18 18:19
• Updated: 28/Feb/19 17:44
• Resolved: 06/Feb/19 05:17

Description

Following up on PDFBOX-4392 I have noticed ICC color spaces aren't being cached in the resource cache, since they are represented not by a `COSObject` but rather by a `COSArray` with `COSName` of `ICCBased` as the first element and a `COSObject` (the actual profile) as the second element.  

This patch introduces a static `create` method to `PDICCBased` which optionally caches/retrieves the color space from cache. Accordingly, the constructor taking a `COSArray` has been made private, and the validity tests moved to the static `create` method.   

Testing on the example from PDFBOX-4392 the patch improves both time and memory consumption. Presumably it will help with any PDF with ICC-based profiles which are re-used by many images.